The glycosides of phytosterols, including cholesterol, are called sterolines. Phytosterols and their glycosides occur in nature in small amounts in all plants and often in microorganisms. It is possible to produce sterolines synthetically in relatively large yields by means of the known Konigs-Knorr synthesis with the use of the corresponding aglycones and a sugar acetate bromided at the C-1 position with the use of silver or cadmium catalysts. In nature, sterolines mostly occur in the form of monoglycosides, although some oligoglycosides are known. Additionally, sterolines occur in natural vegetable matter, partially also in the form of esters, namely in monobasic monocarboxylic acids.
Mono- to triglycosides, derived from steroid saponine alcohols, which have a spiroketaline grouping connected in the C-16 and C-17 position of the steroid shell of aglycone, are called spiroketalines. The aglycones can be classified either as 5-En-steroid sapogenines or as 5-.alpha.-steroid sapogenines. In natural saponine material the aglycones are mainly present as glycosides and contain 3 or possibly more coupled monosaccharide units and can be hydrolytically decomposed to spiroketalines by means of enzymes. Synthesis of spiroketalines by the Konigs-Knorr method is also possible with good yields. It has been known for a long time that both sterolines as well as spiroketalines exhibit a multitude of pharmacological activities because they interact at the prostaglandinesynthetase level, as known from British Patent 2 039 217, as well as at the lipoxygenase level, as known from German Published, Non-examined Application DE-OS 34 16 112, for example. Thus sterolines and spiroketalines can be used not only for the treatment of inflammatory conditions, but also wherever it is necessary to normalize the arachidonic acid balance, for example with asthma, acne, psoriasis, abdominal rheumatism, gastric and intestinal ulcers, and thrombophlebitis.
Up to now, in the use of sterolines in particular, it has been shown that excellent results in the course of in vitro testing could not be reproduced in vivo. In J. Pharm Sci., 1985, 74, pp 1259, J. Seki et al have noted an intestinal absorption of sitosterol glycoside of only 1 to 2%. This often occurs because the extremely poor water solubility of the sterolines and the poor water solubility of spiroketalines makes it impossible to achieve sufficient resorption and thus blood levels. For this reason there has been a previous attempt to improve resorption, for example by reducing the particle size, by using more highly water-soluble derivatives such as hemiesters, or by using solubilizers, such as recited, for example, in U.S. Pat. No. 3,966,918. Tests using substances marked with .sup.14 C, however, clearly show that resorption can only be slightly improved by use of a micronizer or other reduction of the particle size, and that this is also true when an attempt is made to increase the amount of the compounds in the aqueous solution by using solubilizers.
Thus there is still a need for pharmaceutical preparations containing sterolines and/or spiroketalines and having better resorptivity.